Method for improving fluidity of iron-making raw materials and iron-making method

Abstract

To provide a fluidity improver for iron-making raw materials with excellent fluidity, a method for improving the fluidity of iron-making raw materials using the fluidity improver, and an iron-making method using the fluidity improver for iron-making raw materials. 【Solution means】The fluidity improver for iron-making raw materials contains an ester compound. The flash point of the ester compound is 250°C or higher. The kinematic viscosity of the ester compound at 40°C is 1.0×10 -4 m 2 / s or less. The solubility of the ester compound in water at 25°C is less than 1 g / 100 g.

Description

Technical Field

[0001] The present invention relates to an agent for improving the fluidity of iron-making raw materials, a method for improving the fluidity of iron-making raw materials, and an iron-making method.

Background Art

[0002] Conventionally, it has been known to produce steel from iron-making raw materials (for example, coal, iron ore, limestone, recovered dust from each iron-making process, etc.). Specifically, coal is coked to produce coke, iron ore and limestone are sintered to produce sintered ore, and further, steel is produced using the coke and the sintered ore.

[0003] In the production of coke, a method for improving the bulk density of coal for coke production has been proposed in which polyoxyethylene alkyl ether sulfate (a bulk density improver) is added to coal (for example, see Patent Document 1 below).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] On the other hand, when iron-making raw materials are received and stored in a raw material storage location, moisture adheres to the iron-making raw materials, and due to the moisture, the fluidity of the iron-making raw materials decreases, resulting in a problem of reduced productivity. In addition, although iron-making raw materials are transported using transportation equipment (for example, conveyors, chutes, liners, rotary valves, and hoppers), there is a problem that the iron-making raw materials stick to the transportation equipment, reducing the transportability. Therefore, improving the fluidity of iron-making raw materials has been considered.

[0006] The present invention provides a fluidity improver for iron-making raw materials with excellent fluidity, a method for improving the fluidity of iron-making raw materials using the fluidity improver for iron-making raw materials, and an iron-making method using the fluidity improver for iron-making raw materials.

Means for Solving the Problems

[0007] The present invention [1] includes an ester compound, the flash point of the ester compound is 250°C or higher, the kinematic viscosity of the ester compound at 40°C is 1.0×10 -4 m 2 / s or less, and the solubility of the ester compound in water at 25°C is less than 1 g / 100 g, which is a fluidity improver for iron-making raw materials.

[0008] The present invention [2] further includes a mineral oil and contains the fluidity improver for iron-making raw materials described in the above [1].

[0009] The present invention [3] includes the fluidity improver for iron-making raw materials described in the above [1] or [2], wherein the ester compound is a monoester compound.

[0010] The present invention [4] includes a method for improving the fluidity of iron-making raw materials, which comprises blending the fluidity improver for iron-making raw materials described in any one of the above [1] to [3] with the iron-making raw materials.

[0011] The present invention [5] includes a first step of carbonizing a first iron-making raw material containing coal to produce coke, a second step of sintering a second iron-making raw material containing iron ore to produce sintered ore, and a third step of producing steel from the coke and the sintered ore, and blending the fluidity improver for iron-making raw materials described in any one of the above [1] to [3] with the first iron-making raw material in the first step and / or the second iron-making raw material in the second step, which is an iron-making method.

Effects of the Invention

[0012] The fluidity improver for iron-making raw materials of the present invention contains an ester compound, the flash point of the ester compound is 250°C or higher, the kinematic viscosity of the ester compound at 40°C is -4 m 2 / s or less, and the solubility of the ester compound in water at 25°C is less than 1 g / 100 g. Therefore, the fluidity can be improved.

[0013] The method for improving the fluidity of iron-making raw materials of the present invention is to blend the fluidity improver for iron-making raw materials of the present invention with the iron-making raw materials. Therefore, the fluidity can be improved.

[0014] The iron-making method of the present invention is to blend the fluidity improver for iron-making raw materials of the present invention with the first iron-making raw material in the first step and / or the second iron-making raw material in the second step. Therefore, the fluidity can be improved.

Embodiments for Carrying Out the Invention

[0015] 1. Fluidity Improver for Iron-Making Raw Materials The fluidity improver for iron-making raw materials (hereinafter, may be referred to as the fluidity improver) improves (enhances) the fluidity of the iron-making raw materials.

[0016] The iron-making raw materials are raw materials for manufacturing steel.

[0017] The iron-making raw materials are preferably powdery or granular. The average particle diameter of the iron-making raw materials is, for example, 0.1 μm to 100 mm, preferably 10 μm to 10 mm.

[0018] Examples of the iron-making raw materials include coal, iron ore, limestone, quicklime, slag, and dust collected.

[0019] The iron-making raw materials may be single or the above mixtures.

[0020] The fluidity improver contains an ester compound.

[0021] <Ester Compound> The ester compound has one or more ester groups in one molecule and does not have a hydroxyl group and a carboxyl group.

[0022] Also, the ester compound is a reaction product of an acid (carboxylic acid) and an alcohol.

[0023] Preferably, among the acid and the alcohol, at least one of them has 10 or more and 30 or less carbon atoms.

[0024] Examples of the ester compound include a monoester compound, a diester compound, a triester compound, and a tetraester compound.

[0025] [Monoester compound] Examples of the monoester compound include reaction products of a monocarboxylic acid and a monool.

[0026] Examples of the monocarboxylic acid include aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, and aromatic monocarboxylic acids. Preferably, the monocarboxylic acid is an aliphatic monocarboxylic acid.

[0027] Examples of the aliphatic monocarboxylic acid include saturated aliphatic monocarboxylic acids and unsaturated aliphatic monocarboxylic acids.

[0028] Examples of the saturated aliphatic monocarboxylic acid include linear saturated aliphatic monocarboxylic acids having 10 or more and 30 or less carbon atoms.

[0029] Examples of the saturated aliphatic monocarboxylic acid having 10 or more and 30 or less carbon atoms include decanoic acid (capric acid), undecanoic acid, dodecanoic acid (lauric acid), tridecanoic acid, tetradecanoic acid (myristic acid), pentadecanoic acid, hexadecanoic acid (palmitic acid), heptadecanoic acid (margaric acid), octadecanoic acid (stearic acid), nonadecanoic acid, and eicosanoic acid.

[0030] Examples of the unsaturated aliphatic monocarboxylic acid include linear unsaturated aliphatic monocarboxylic acids having 10 to 30 carbon atoms.

[0031] Examples of the linear unsaturated aliphatic monocarboxylic acid having 10 to 30 carbon atoms include myristoleic acid, palmitoleic acid, oleic acid, elaidic acid, vaccenic acid, and eicosenoic acid. Preferably, the linear unsaturated aliphatic monocarboxylic acid having 10 to 30 carbon atoms is oleic acid.

[0032] From the viewpoint of improving fluidity, the aliphatic monocarboxylic acid is preferably an unsaturated aliphatic monocarboxylic acid.

[0033] The monocarboxylic acid can be used alone or in combination of two or more.

[0034] Examples of the monool include aliphatic monools, alicyclic monools, and aromatic monools. Preferably, the monool is an aliphatic monool.

[0035] Examples of the aliphatic monool include linear aliphatic monools and branched aliphatic monools.

[0036] Examples of the linear aliphatic monool include linear aliphatic monools having 1 to 9 carbon atoms and linear aliphatic monools having 10 to 30 carbon atoms.

[0037] Examples of the linear aliphatic monool having 1 to 9 carbon atoms include methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, and 1-nonanol.

[0038] Examples of the straight-chain aliphatic monohydric alcohols having 10 to 30 carbon atoms include 1-decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, 1-tetradecanol, 1-pentadecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol, 1-nonadecanol, and 1-eicosanol.

[0039] Examples of the branched aliphatic monohydric alcohols include branched aliphatic monohydric alcohols having 1 to 9 carbon atoms and branched aliphatic monohydric alcohols having 10 to 30 carbon atoms.

[0040] Examples of the branched aliphatic monohydric alcohols having 1 to 9 carbon atoms include 2-ethylhexanol.

[0041] Examples of the branched aliphatic monohydric alcohols having 10 to 30 carbon atoms include 2-propylheptanol, 2-butyloctanol, 1-methylheptadecanol, 2-hexyloctanol, 1-hexylheptanol, isooctanol, isodecanol, and isotridecanol.

[0042] Preferred aliphatic monohydric alcohols are branched aliphatic monohydric alcohols. More preferred aliphatic monohydric alcohols are branched aliphatic monohydric alcohols having 10 to 30 carbon atoms.

[0043] The monohydric alcohol can be used alone or in combination of two or more.

[0044] The monoester compound is obtained by subjecting a monocarboxylic acid (1 mol) and a monohydric alcohol (1 mol) to an esterification reaction.

[0045] Preferred monoester compounds include the reaction product of oleic acid and isotridecanol (isotridecyl oleate).

[0046] [Diester Compound] Examples of diester compounds include reaction products of monocarboxylic acids and diols, and reaction products of dicarboxylic acids and monools.

[0047] Examples of dicarboxylic acids include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids. Preferred examples of the dicarboxylic acid include aliphatic dicarboxylic acids.

[0048] Examples of aliphatic dicarboxylic acids include saturated dicarboxylic acids and unsaturated dicarboxylic acids.

[0049] Examples of saturated dicarboxylic acids include saturated dicarboxylic acids having 1 to 9 carbon atoms and saturated dicarboxylic acids having 10 to 30 carbon atoms.

[0050] Examples of saturated dicarboxylic acids having 1 to 9 carbon atoms include ethanedioic acid (oxalic acid), propanedioic acid (malonic acid), n-butanedioic acid (succinic acid), n-heptanedioic acid (glutaric acid), n-hexanedioic acid (adipic acid), n-heptanedioic acid, n-octanedioic acid, and n-nonanedioic acid (azelaic acid).

[0051] Examples of saturated dicarboxylic acids having 10 to 30 carbon atoms include n-decanedioic acid (sebacic acid), n-undecanedioic acid, n-dodecanedioic acid, n-tridecanedioic acid, n-tetradecanedioic acid, n-pentadecanedioic acid, and n-hexadecanedioic acid.

[0052] Examples of unsaturated dicarboxylic acids include unsaturated dicarboxylic acids having 1 to 9 carbon atoms. Examples of unsaturated dicarboxylic acids having 1 to 9 carbon atoms include maleic acid, fumaric acid, and itaconic acid.

[0053] The dicarboxylic acids can be used alone or in combination of two or more.

[0054] Examples of the diol include aliphatic diols, alicyclic diols, and aromatic diols. Preferred examples of the diol include aliphatic diols.

[0055] Examples of the diol include diols having 1 to 9 carbon atoms. Examples of the diol having 1 to 9 carbon atoms include ethylene glycol, propylene glycol, butylene glycol, 1,5-pentanediol, 1,6-hexanediol, and neopentyl glycol. Preferred examples of the diol having 1 to 9 carbon atoms include neopentyl glycol.

[0056] The diol can be used alone or in combination of two or more.

[0057] The diester compound is obtained by subjecting (2 moles of) a monocarboxylic acid and (1 mole of) a diol to an esterification reaction, or subjecting (1 mole of) a dicarboxylic acid and (2 moles of) a monoalcohol to an esterification reaction.

[0058] Preferred examples of the diester compound include the reaction product of oleic acid and neopentyl glycol (neopentyl glycol dioleate).

[0059] [Triester compound] Examples of the triester compound include the reaction product of a tricarboxylic acid and a monoalcohol, and the reaction product of a monocarboxylic acid and a triol.

[0060] Examples of the tricarboxylic acid include aliphatic tricarboxylic acids, alicyclic tricarboxylic acids, and aromatic tricarboxylic acids. Preferred examples of the tricarboxylic acid include aliphatic tricarboxylic acids.

[0061] Examples of the aliphatic tricarboxylic acid include saturated aliphatic tricarboxylic acids and unsaturated aliphatic tricarboxylic acids.

[0062] Examples of saturated aliphatic tricarboxylic acids include saturated aliphatic tricarboxylic acids having 1 to 9 carbon atoms and saturated aliphatic tricarboxylic acids having 10 to 30 carbon atoms.

[0063] Examples of saturated aliphatic tricarboxylic acids having 1 to 9 carbon atoms include butane tricarboxylic acid and pentane tricarboxylic acid.

[0064] Examples of saturated aliphatic tricarboxylic acids having 10 to 30 carbon atoms include hexane tricarboxylic acid and octane tricarboxylic acid.

[0065] Examples of unsaturated aliphatic tricarboxylic acids include unsaturated aliphatic tricarboxylic acids having 1 to 9 carbon atoms. Examples of unsaturated aliphatic tricarboxylic acids having 1 to 9 carbon atoms include aconitic acid.

[0066] The tricarboxylic acids can be used alone or in combination of two or more.

[0067] Examples of triols include aliphatic triols, alicyclic triols, and aromatic triols. Preferably, the triol is an aliphatic triol.

[0068] Examples of aliphatic triols include aliphatic triols having 1 to 9 carbon atoms. Examples of aliphatic triols having 1 to 9 carbon atoms include trimethylolethane, trimethylolpropane, trimethylolbutane, glycerin, and 1,3,5-pentanetriol. Preferably, the aliphatic triol having 1 to 9 carbon atoms is trimethylolpropane.

[0069] The triol can be used alone or in combination of two or more.

[0070] The triester compound is obtained by subjecting tricarboxylic acid (1 mol) and monoalcohol (3 mol) to an esterification reaction, or subjecting monocarboxylic acid (3 mol) and triol (1 mol) to an esterification reaction.

[0071] As the triester compound, preferably, a reaction product of monocarboxylic acid and triol can be mentioned. As the triester compound, more preferably, a reaction product of oleic acid and trimethylolpropane (trimethylolpropane trioleate) can be mentioned.

[0072] [Tetraester compound] Examples of the tetraester compound include a reaction product of tetracarboxylic acid and monoalcohol, and a reaction product of monocarboxylic acid and tetraol.

[0073] Examples of the tetracarboxylic acid include aliphatic tetracarboxylic acid, alicyclic tetracarboxylic acid, and aromatic tetracarboxylic acid. As the tetracarboxylic acid, preferably, aliphatic tetracarboxylic acid can be mentioned.

[0074] Examples of the aliphatic tetracarboxylic acid include saturated aliphatic tetracarboxylic acid and unsaturated aliphatic tetracarboxylic acid.

[0075] Examples of the saturated aliphatic tetracarboxylic acid include saturated aliphatic tetracarboxylic acid having 1 to 9 carbon atoms and saturated aliphatic tetracarboxylic acid having 10 to 30 carbon atoms.

[0076] Examples of the saturated aliphatic tetracarboxylic acid having 1 to 9 carbon atoms include butanetetracarboxylic acid.

[0077] Examples of the saturated aliphatic tetracarboxylic acid having 10 to 30 carbon atoms include octanetetracarboxylic acid.

[0078] Examples of the saturated aliphatic tetracarboxylic acid include saturated aliphatic tetracarboxylic acids having 1 to 9 carbon atoms. Examples of the saturated aliphatic tetracarboxylic acid having 1 to 9 carbon atoms include 4-pentene-1,2,3,4-tetracarboxylic acid.

[0079] The tetracarboxylic acid can be used alone or in combination of two or more.

[0080] Examples of the tetraol include aliphatic tetraols, alicyclic tetraols, and aromatic tetraols. Preferably, the tetraol is an aliphatic tetraol.

[0081] Examples of the aliphatic tetraol include aliphatic tetraols having 1 to 9 carbon atoms. Examples of the aliphatic tetraol having 1 to 9 carbon atoms include pentaerythritol and diglycerin. Preferably, the aliphatic tetraol having 1 to 9 carbon atoms is pentaerythritol.

[0082] The tetraol can be used alone or in combination of two or more.

[0083] The tetraester compound can be obtained by subjecting tetracarboxylic acid (1 mol) and monoalcohol (4 mol) to an esterification reaction, or subjecting monocarboxylic acid (4 mol) and tetraol (1 mol) to an esterification reaction.

[0084] Preferably, the tetraester compound is a reaction product of monocarboxylic acid and tetraol. More preferably, the tetraester compound is a reaction product of oleic acid and pentaerythritol (pentaerythritol tetraoleate).

[0085] Examples of the ester compound include monoester compounds from the viewpoint of further improving fluidity.

[0086] Further, the flash point of the ester compound is 250 °C or higher, and for example, 350 °C or lower, preferably 330 °C or lower, more preferably 310 °C or lower.

[0087] If the flash point of the ester compound is at or above the above lower limit, the availability can be improved.

[0088] The flash point can be measured by a Cleveland open cup flash point tester.

[0089] Also, the kinematic viscosity of the ester compound at 40 °C is 1.00×10 -4 m 2 / s or less, preferably 0.80×10 -4 m 2 / s or less, more preferably 0.60×10 -4 m 2 / s or less, even more preferably 0.40×10 -4 m 2 / s or less, particularly preferably 0.20×10 -4 m 2 / s or less, most preferably 0.15×10 -4 m 2 / s or less, and for example, 0.01×10 -4 m 2 / s or more.

[0090] If the kinematic viscosity of the ester compound at 40 °C is at or below the above upper limit, the fluidity can be improved.

[0091] On the other hand, when the kinematic viscosity of the ester compound at 40 °C exceeds the above upper limit, the fluidity decreases.

[0092] The kinematic viscosity at 40 °C can be measured based on JIS K 2283.

[0093] The solubility of the ester compound in water at 25 °C is less than 1 g / 100 g, and for example, 0.01 g / 100 g or more.

[0094] That is, the ester compound is an oil that is substantially insoluble in water (in other words, ester oil), and is distinguished from, for example, a surfactant.

[0095] If the above solubility is below the above upper limit, the fluidity can be improved.

[0096] If the above solubility exceeds the above upper limit, the fluidity decreases.

[0097] The method for measuring the above solubility will be described in detail in the examples described later.

[0098] The hydroxyl value of the ester compound is, for example, 0.5 mgKOH / g or less, preferably 0.1 mgKOH / g or less.

[0099] The hydroxyl value of the ester compound can be measured according to the acetylation method or phthalation method based on Method A or Method B of JIS K1557-1.

[0100] The acid value of the ester compound is, for example, 0.5 mgKOH / g or less, preferably 0.1 mgKOH / g or less.

[0101] The acid value of the ester compound can be measured according to JIS K 0070-1992 (potentiometric titration method).

[0102] The iodine value of the ester compound is, for example, 0.1 gl / 100g to 100 gl / 100g, preferably 40 gl / 100g to 80 gl / 100g.

[0103] The iodine value of the ester compound can be measured according to JIS K0070.

[0104] The ester compound can be used alone or in combination of two or more.

[0105] The content ratio of the ester compound will be described later.

[0106] In the above description, in the diester compound, either one of the carboxylic acid and the alcohol is monofunctional, but both the carboxylic acid and the alcohol may be bifunctional. Specifically, the diester compound may be a reaction product of a dicarboxylic acid and a diol. That is, as long as the carboxyl group of the carboxylic acid and the hydroxyl group of the alcohol are in equal amounts, the number of functional groups of the carboxylic acid and the alcohol is not limited. This also applies to triester compounds and tetraester compounds.

[0107] <Mineral oil> The fluidity improver may contain mineral oil if necessary. If the fluidity improver contains mineral oil, the bulk of the fluidity improver can be increased while maintaining the fluidity improving effect, so that productivity can be improved.

[0108] Mineral oil is an oil obtained by separating, distilling, and purifying natural crude oil.

[0109] Examples of mineral oil include paraffinic hydrocarbons and naphthenic hydrocarbons. Preferably, paraffinic hydrocarbons are mentioned as the mineral oil.

[0110] Mineral oil can be used alone or in combination of two or more.

[0111] The content ratio of the mineral oil will be described later.

[0112] <Manufacturing method of fluidity improver> The fluidity improver is obtained by mixing an ester compound and, if necessary, a mineral oil to be blended.

[0113] When the fluidity improver contains an ester compound and a mineral oil, the content ratio of the ester compound is, for example, 20% by mass to 99% by mass, preferably 30% by mass to 95% by mass, more preferably 50% by mass to 90% by mass, still more preferably 60% by mass to 88% by mass, particularly preferably 75% by mass to 85% by mass, with respect to the ester compound and the mineral oil.

[0114] Specifically, the content ratio of the ester compound is, for example, 20% by mass or more, preferably 30% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more, particularly preferably 75% by mass or more, and, for example, 99% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, still more preferably 88% by mass or less, particularly preferably 85% by mass or less, with respect to the ester compound and the mineral oil.

[0115] If the content ratio of the ester compound is equal to or higher than the above lower limit and equal to or lower than the above upper limit, the fluidity can be further improved.

[0116] In addition, the content ratio of the mineral oil is, for example, 1% by mass to 80% by mass, preferably 5% by mass to 70% by mass, more preferably 10% by mass to 50% by mass, still more preferably 12% by mass to 40% by mass, particularly preferably 15% by mass to 25% by mass, with respect to the ester compound and the mineral oil.

[0117] Specifically, the content ratio of the mineral oil is, for example, 1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 12% by mass or more, particularly preferably 15% by mass or more, and, for example, 80% by mass or less, preferably 70% by mass, more preferably 50% by mass or less, still more preferably 40% by mass or less, particularly preferably 25% by mass or less, with respect to the ester compound and the mineral oil.

[0118] If the content ratio of the mineral oil is equal to or higher than the above lower limit, the fluidity improver can be bulked up while maintaining the fluidity improvement effect, so that the productivity can be improved.

[0119] If the content ratio of the mineral oil is equal to or lower than the above upper limit, the viscosity change due to the temperature change of the mineral oil can be suppressed. As a result, the reliability can be improved.

[0120] Thereby, a fluidity improver is produced.

[0121] 2. Method for Improving Fluidity of Ironmaking Raw Materials In the method for improving the fluidity of ironmaking raw materials, a fluidity improver is blended with the ironmaking raw materials. Specifically, the ironmaking raw materials and the fluidity improver are kneaded by a known kneading device (mill, kneader, mixer), and / or by transferring the raw materials through conveying equipment (conveyor, chute, liner, rotary feeder).

[0122] As the kneading conditions, the kneading time is, for example, 1 minute to 120 minutes.

[0123] The blending ratio of the fluidity improver is, for example, 0.010% by mass to 2.000% by mass, preferably 0.050% by mass to 1.300% by mass, more preferably 0.100% by mass to 0.900% by mass, still more preferably 0.120% by mass to 0.600% by mass, and particularly preferably 0.140% by mass to 0.480% by mass, based on the total amount of the ironmaking raw materials and the fluidity improver.

[0124] Specifically, the blending ratio of the fluidity improver is, for example, 0.010% by mass or more, preferably 0.050% by mass or more, more preferably 0.100% by mass or more, still more preferably 0.120% by mass or more, and particularly preferably 0.140% by mass or more, and, for example, 2.000% by mass or less, preferably 1.300% by mass or less, more preferably 0.900% by mass or less, still more preferably 0.600% by mass or less, and particularly preferably 0.480% by mass or less.

[0125] If the blending ratio of the fluidity improver is equal to or higher than the above lower limit, the fluidity can be improved.

[0126] If the blending ratio of the fluidity improver is equal to or lower than the above upper limit, stickiness caused by the fluidity improver can be suppressed, and the fluidity can be improved.

[0127] And in the method for improving the fluidity of ironmaking raw materials, since a fluidity improver is blended with the ironmaking raw materials, the fluidity can be improved.

[0128] In the above description, a fluidity improver is produced by previously mixing an ester compound and, if necessary, a mineral oil to be blended, and then this fluidity improver is blended into the iron-making raw material. However, when using the fluidity improver, it is also possible to blend the ester compound and, if necessary, the mineral oil to be blended into the iron-making raw material.

[0129] 3. Iron-making method The iron-making method includes a first step of carbonizing a first iron-making raw material containing coal to produce coke, a second step of sintering a second iron-making raw material containing iron ore to produce sintered ore, and a third step of producing steel from the coke and the sintered ore.

[0130] In this iron-making method, a fluidity improver is blended into the first iron-making raw material in the first step and / or the second iron-making raw material in the second step.

[0131] In the following description, the case where a fluidity improver is blended into both the first iron-making raw material in the first step and the second iron-making raw material in the second step will be described in detail.

[0132] <First step> In the first step, the first iron-making raw material is carbonized to produce coke.

[0133] To carbonize the first iron-making raw material to produce coke, first, a fluidity improver is blended into the first iron-making raw material in the first step.

[0134] The first iron-making raw material contains at least coal. The first iron-making raw material preferably contains dust together with coal.

[0135] In the first step, the blending ratio of the fluidity improver to the total amount of the first iron-making raw material and the fluidity improver is the same as the blending ratio of the fluidity improver to the total amount of the above-described iron-making raw material and the fluidity improver.

[0136] Next, the first iron-making raw material is carbonized to produce coke. Specifically, the first iron-making raw material is transported to a coke oven, and in the coke oven, the first iron-making raw material is carbonized based on known conditions to produce coke.

[0137] <Second Step> In the second step, the second iron-making raw material containing iron ore is sintered to produce sintered ore.

[0138] To sinter the second iron-making raw material to produce sintered ore, first, a fluidity improver is blended with the second iron-making raw material in the second step.

[0139] The second iron-making raw material contains at least iron ore. The second iron-making raw material preferably contains limestone, quicklime, and dust collected together with the iron ore.

[0140] In the second step, the blending ratio of the fluidity improver to the total amount of the second iron-making raw material and the fluidity improver is the same as the blending ratio of the fluidity improver to the total amount of the above-described iron-making raw material and the fluidity improver.

[0141] Next, the second iron-making raw material is sintered to produce sintered ore. Specifically, the second iron-making raw material is transported to a sintering furnace, and in the sintering furnace, the second iron-making raw material is sintered based on known conditions to produce sintered ore.

[0142] <Third Step> In the third step, steel is produced from coke and sintered ore.

[0143] Specifically, coke and sintered ore are transported to a blast furnace, and pig iron is produced based on known conditions. Next, the pig iron is transported to a converter, and steel is produced based on known conditions.

[0144] And in this iron-making method, a fluidity improver is blended with the first iron-making raw material in the first step and the second iron-making raw material in the second step. Therefore, the fluidity can be improved.

[0145] In the above description, a fluidity improver is blended in both the first iron-making raw material in the first step and the second iron-making raw material in the second step. However, the fluidity improver can also be blended in either one of the first iron-making raw material in the first step and the second iron-making raw material in the second step. Specifically, the fluidity improver may not be blended in the first iron-making raw material in the first step and may be blended in the second iron-making raw material in the second step, or the fluidity improver may not be blended in the second iron-making raw material in the second step and may be blended in the first iron-making raw material in the first step.

[0146] In the above description, the iron-making method is carried out in the order of the first step, the second step, and the third step. However, if the first step and the second step are carried out before the third step, the order is not limited.

[0147] Specifically, it can also be carried out in the order of the second step, the first step, and the third step, or the third step can be carried out after the first step and the second step are carried out simultaneously.

[0148] 4. Effects The fluidity improver contains an ester compound. The flash point of the ester compound is 250°C or higher, the kinematic viscosity of the ester compound at 40°C is 1.0×10 -4 m 2 / s or less, and the solubility of the ester compound in water at 25°C is less than 1 g / 100 g. Therefore, the fluidity can be improved.

[0149] Specifically, when the iron-making raw material is received and stored in the raw material storage location, moisture adheres to the iron-making raw material, and due to this moisture, the fluidity of the iron-making raw material decreases, resulting in a problem of reduced productivity. In addition, the iron-making raw material is transported using transportation equipment (for example, conveyors, chutes, liners, rotary valves, and hoppers), but there is a problem that the iron-making raw material adheres to the transportation equipment, reducing the transportability. Therefore, improving the fluidity of the iron-making raw material is considered.

[0150] As a method for improving the fluidity of iron-making raw materials, a method of drying the moisture adhering to the iron-making raw materials is considered.

[0151] However, in order to dry the moisture adhering to the iron-making raw materials, there is a problem that productivity decreases because it requires a predetermined time and / or large-scale equipment.

[0152] Also, as a method for improving the fluidity of iron-making raw materials, a method of previously molding the iron-making raw materials is considered.

[0153] However, this method has a problem that productivity decreases because the iron-making raw materials are molded in advance.

[0154] Also, as a method for improving the fluidity of iron-making raw materials, a method of blending heavy oil into the iron-making raw materials is considered.

[0155] However, heavy oil has a problem of low flash point.

[0156] Also, as a method for improving the fluidity of iron-making raw materials, a method of blending a surfactant into the iron-making raw materials is considered.

[0157] However, from the viewpoint of further improving productivity, a further improvement in fluidity is required.

[0158] On the other hand, the fluidity improver can improve the fluidity only by blending it into the iron-making raw materials. Therefore, productivity can be improved.

[0159] Also, the fluidity improver contains an ester compound, the flash point of the ester compound is 250 °C or higher, the kinematic viscosity of the ester compound at 40 °C is 1.0×10 -4 m 2 / s or less, and the solubility of the ester compound in water at 25 °C is less than 1 g / 100 g.

[0160] That is, the fluidity improver contains an ester oil having a high flash point and a low kinematic viscosity.

[0161] By coating the surface of the iron-making raw material with such an ester oil, the fluidity of the iron-making raw material can be improved.

[0162] In addition, the fluidity improver improves the bulk density of the iron-making raw material by improving the fluidity of the iron-making raw material.

[0163] On the other hand, by improving the bulk density of the iron-making raw material, the strength of the coke and iron ore obtained using the iron-making raw material can also be improved.

Examples

[0164] Examples and comparative examples are shown below to explain the present invention more specifically. Note that the present invention is not limited to any examples and comparative examples. Also, specific numerical values such as the blending ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values (numerical values defined as "below" and "less than") or lower limit values (numerical values defined as "above" and "exceeding") of the corresponding blending ratio (content ratio), physical property values, parameters, etc. described in the above "Mode for Carrying Out the Invention".

[0165] <Details of Components> The trade names and abbreviations of the components used in each example and each comparative example will be described in detail. Isotridecyl oleate: flash point 250 °C or higher, kinematic viscosity (40 °C) 0.14×10 -4 m 2 / s, solubility in water at 25 °C less than 1 g / 100 g, acid value 0.5 mg KOH / g or less, hydroxyl value 0.5 mg KOH / g or less, commercially available product Neopentyl glycol dioleate: flash point 250 °C or higher, kinematic viscosity (40 °C) 0.18×10 -4 m 2 / s, solubility in water at 25 °C less than 1 g / 100 g, acid value 0.5 mg KOH / g or less, hydroxyl value 0.5 mg KOH / g or less, commercially available product Trimethylolpropane trioleate: flash point 270°C or higher, kinematic viscosity (40°C) 0.47×10 -4 m 2 / s, solubility in water at 25°C less than 1 g / 100 g, acid value 0.5 mg KOH / g or less, hydroxyl value 0.5 mg KOH / g or less, commercially available product Pentaerythritol tetraoleate: flash point 300°C or higher, kinematic viscosity (40°C) 0.68×10 -4 m 2 / s, solubility in water at 25°C less than 1 g / 100 g, acid value 0.5 mg KOH / g or less, hydroxyl value 0.5 mg KOH / g or less, commercially available product K68: paraffinic mineral oil, trade name "Super Oil K68", manufactured by ENEOS BJ100: paraffinic mineral oil, trade name "Shell Morlina S1 BJ 100", manufactured by Shell Alscop DA-330S: anionic surfactant, sodium polyoxyethylene alkyl (C12, 13) ether sulfate (3 E.O.), trade name "Alscop DA-330S", solubility in water at 25°C 1 g / 100 g or more, manufactured by Toho Chemical Fine Surf 230: nonionic surfactant, polyoxyethylene secondary alcohol ether (3 E.O.) trade name "Fine Surf 230, solubility in water at 25°C 1 g / 100 g or more, manufactured by Aoki Yushi

[0166] <Manufacture of fluidity improver> Examples 1 to 14, and Comparative Examples 1 to 5 Based on the formulation shown in Table 1, 200 g (water content 9.5%) of pulverized coal (iron-making raw material) that had passed through a sieve (mesh size 3 mm) was mixed with each component (ester compound, mineral oil, anionic surfactant, nonionic surfactant, and oleic acid), and kneaded for 1 minute using a pot mixer.

[0167] Thereby, a kneaded product containing a fluidity improver and coal was obtained. The numerical values of each component in Table 1 are the blending ratios of each component with respect to the total amount of coal and each component.

[0168] Examples 15 to 17 and Comparative Example 6 Based on the formulation shown in Table 2, each component was mixed with 100 g (water content: 9.5%) of granular coal (iron-making raw material) that had passed through a sieve (mesh size: 3 mm), and kneaded for 1 minute using a pot mixer.

[0169] Thereby, a kneaded product containing a fluidity improver and coal was obtained. Note that the numerical values of each component in Table 2 are the blending ratios of each component with respect to the total amount of coal and each component.

[0170] Ratio Comparative Example 7 Based on the formulation shown in Table 2, each component was mixed with 200 g (water content: 9.5%) of granular iron oxide (iron-making raw material) that had passed through a sieve (mesh size: 3 mm), and kneaded for 1 minute using a pot mixer. Note that iron oxide is a substitute for iron ore and dust collected from a dust collector, and contains divalent iron and trivalent iron.

[0171] Thereby, a kneaded product containing a fluidity improver and iron oxide was obtained. Note that the numerical values of each component in Table 2 are the blending ratios of each component with respect to the total amount of iron oxide and each component.

[0172] <Evaluation> (Flash point) The flash points of the ester compounds of each example were measured using a Cleveland open cup flash point tester. The results are shown in Tables 1 and 2.

[0173] (Kinematic viscosity) The kinematic viscosities at 40°C of the ester compounds of each example were measured based on JIS K 2283. The results are shown in Tables 1 and 2.

[0174] (Solubility in water at 25°C) For the ester compounds of each example and the surfactants of each comparative example, the solubility in water at 25 °C was measured. Specifically, in an environment of 25 °C, 19.80 g of water was placed in a test tube with a lid, and 0.20 g of a sample (the ester compound of each example and the surfactant of each comparative example) was added to the water. The mixture was shaken 100 times and left standing for 1 hour. Then, the upper part of the liquid surface was visually observed. When an oil film remained on the upper part of the liquid surface, it was judged that the solubility in water at 25 °C was less than 1%. On the other hand, when no oil film remained on the upper part of the liquid surface, it was judged that the solubility in water at 25 °C was 1% or more. The results are shown in Table 1 and Table 2.

[0175] (Flowability) [Bulk density] The experimental conditions were 20 °C and a humidity of 60%. First, a funnel was prepared and plugged at the lower end opening. Next, the kneaded materials of Examples 1 to 14 and Comparative Examples 1 to 5 were charged from the upper end opening (diameter 12 cm) of the funnel. Specifically, the charging was carried out until the height of the kneaded material reached 45 cm from the lower end opening.

[0176] Next, a cylindrical stainless steel cup (height 10 cm, diameter 5 cm) was prepared. The upper end opening of the cylindrical stainless steel cup was connected to the lower end opening of the funnel, and the plug at the lower end opening of the funnel was removed. As a result, the kneaded material in the funnel freely fell toward the cylindrical stainless steel cup. At this time, a part of the kneaded material overflowed from the cylindrical stainless steel cup. Then, the kneaded material overflowing from the upper end opening of the cylindrical stainless steel cup was scraped off using a spatula with a length of 15 cm. Next, the mass of the cylindrical stainless steel cup containing the kneaded material was measured, and the bulk density was calculated from the volume of the cylindrical stainless steel cup.

[0177] The above operations were carried out 10 times in total. With each repetition of the number of times, the bulk density improved. It is presumed that this is due to an increase in the fluidity improver coating the surface of the coal as the coal and the fluidity improver were gradually mixed in the above operations.

[0178] And at the 10th time, the bulk density did not improve. From this, it is inferred that at the 10th time, the coal and the fluidity improver were sufficiently mixed. As the evaluation of the bulk density, the 10th time when the coal and the fluidity improver were sufficiently mixed was adopted.

[0179] Separately, as a blank test, the above operation was carried out 10 times with only 200 g of coal (coal not containing a fluidity improver). Thereby, the test conditions of the blank test were made the same as the test conditions of the 10th time of the bulk density of Examples 1 to 14 and Comparative Examples 1 to 5.

[0180] From the 10th time bulk density of the blank test, the increase rate of the 10th time bulk density of Examples 1 to 14 and Comparative Examples 1 to 5 was calculated. It can be seen that the higher the increase rate of the bulk density, the better the fluidity.

[0181] [Classification Test] The experimental conditions were 20°C and a humidity of 60%. First, in Examples 15 to 17 , Comparative Example 6 and Comparative Example 7, the residue ratio (particle size distribution) of the iron-making raw material (iron-making raw material before blending each component) on each sieve was measured in advance. Specifically, a sieve with an opening of 1 mm and a sieve with an opening of 300 μm were used in this order to classify the iron-making raw material. The classification was carried out by tapping and vibrating the sieve 100 times horizontally. Then, the mass of the iron-making raw material on the 1 mm sieve, the mass of the iron-making raw material on the 300 μm sieve, and the mass of the iron-making raw material under the 300 μm sieve were measured. Then, based on the following formulas (1) to (3), the residue ratio on each sieve was calculated. Residue ratio on the 1 mm sieve = (mass of iron-making raw material on the 1 mm sieve / total mass of iron-making raw material) × 100 (1) Residue ratio on the 300 μm sieve = (mass of iron-making raw material on the 300 μm sieve / total mass of iron-making raw material) × 100 (2) Residue ratio under the 300 μm sieve = (mass of iron-making raw material under the 300 μm sieve / total mass of iron-making raw material) × 100 (3)

[0182] Next, all the iron-making raw materials were recovered, and as described above, each component was blended, mixed, and a kneaded product containing a fluidity improver and the iron-making raw materials was produced. Next, for this kneaded product, the residue ratio in each sieve of the kneaded product was measured according to the same procedure as above.

[0183] Then, based on the following formulas (4) to (6), the increase or decrease rate of the residue ratio in each sieve was calculated. The results are shown in Table 2. It can be seen that the higher the increase or decrease rate of the residue ratio under the 300 μm sieve, the more the adhesion between the iron-making raw materials is suppressed, and the better the fluidity. Increase or decrease rate of the residue ratio on the 1 mm sieve = Residue ratio of the kneaded product on the 1 mm sieve - Residue ratio of the iron-making raw materials on the 1 mm sieve (4) Increase or decrease rate of the residue ratio on the 300 μm sieve = Residue ratio of the kneaded product on the 300 μm sieve - Residue ratio of the iron-making raw materials on the 300 μm sieve (5) Increase or decrease rate of the residue ratio under the 300 μm sieve = Residue ratio of the kneaded product under the 300 μm sieve - Residue ratio of the iron-making raw materials under the 300 μm sieve (6)

[0184] In addition, in Table 2, the residue ratio in each sieve and the increase or decrease rate of the residue ratio in each sieve when coal was classified twice without using a fluidity improver are also listed as Reference Example 1. Also, the residue ratio in each sieve and the increase or decrease rate of the residue ratio in each sieve when iron oxide was classified twice without using a fluidity improver are also listed as Reference Example 2.

[0185]

Table 1

[0186]

Table 2

Claims

1. A first step of producing coke by carbonizing a first ironmaking raw material containing coal; A second step of sintering the second ironmaking raw material containing iron ore to produce sintered ore; and a third step of producing steel from the coke and the sintered ore. In the first step, a flow improver for iron-making raw materials is blended with the first iron-making raw material before the carbonization, The flow improver for the iron-making raw material is Contains an ester compound, The ester compound has a flash point of 250° C. or higher, The ester compound has a kinetic viscosity at 40° C. of 1.0×10 −4 m 2 / s or less; The method for producing iron, wherein the ester compound has a solubility in water at 25°C of less than 1 g / 100 g.

2. A method for producing coke by carbonization comprising blending a flowability improver for ironmaking raw materials with a first ironmaking raw material containing coal; The flow improver for the iron-making raw material is Contains an ester compound, The ester compound has a flash point of 250° C. or higher, The ester compound has a kinematic viscosity at 40° C. of 1.0×10 −4 m 2 / s or less; The method for improving the fluidity of raw materials for iron-making, wherein the ester compound has a solubility in water at 25°C of less than 1 g / 100 g.

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